"We're simply removing a non-essential protein from the cats and it shouldn't hurt the cats in any way," Jackie Avner of Transgenic Pets told the BBC. "The resulting cats will improve the medical health and the quality of life for millions of people."

Thousand dollar pet

Transgenic Pets is working with cattle cloning expert Jerry Yang of the University of Connecticut, US. According to Professor Yang, an allergen-free feline could be available for sale by the year 2003. It would come with a $1,000 (£709) price tag.

The company is still looking for funding to carry out the work. It intends to knock out the gene that codes for the protein linked to human allergic reactions.

"Allergic sensitivity to cats has been attributed to one major protein that is secreted on the cat's skin," said Ms Avner. "The cats that we produce will be like any other cats except they will no longer have the protein that causes an allergic reaction in human beings."

But the plans have been criticised by the UK's Royal Society for the Prevention of Cruelty to Animals (RSPCA).

'Careful consideration'

Vicky Robinson of the Research Animals Department said the work was a trivial application of a technology that already raised serious animal welfare and ethical issues.

"While we sympathise with those people that have allergies we don't think this justifies producing GM cats," she said in a statement.

"Many of the kittens are likely to die before birth and of those that survive there is the very real possibility that they may have abnormalities that compromise their welfare."

Peter Jinman, Junior Vice President of the British Veterinary Association called for public discussion of the issue.

"Instead of changing the environment to suit the animal, we are now looking at changing the animal to fit the environment," he told BBC News Online. "This is a new step that demands very careful consideration."